I voted for the hard tri-fold but really like the BakFlip quad fold, on my 2011 F250 CC short bed, the best. It allows a person to us the entire bed by folding it up against the cab when needed OR it can be totally removed with two hand tighened *****. Also since it is a quad fold a person can run the 5th wheel hitch and leave it folded up at the front of the bed but not standing up against the cab. Then when you aren't towing you can fold it down and cover up the 5th wheel hitch.
The BAKFLIP is a great cover and I haven't been able to find a fault with it yet.
I'm in the market for the BakFlip G2. I was just at your website and noticed that your product description is still for the original G2 and not the second generation. Which one are you selling? I'm looking for one for a 2010 Screw with the 5.5 bed.